Provided is a construction machine capable of restricting halt of a function controlled by a controller when a key switch is in a key-off state. The construction machine includes an interruption switch switched between a supply allowing state of allowing supply of power from a battery to the controller and a supply interruption state of interrupting the power supply; a sensor detecting presence/absence of interruption necessary motion necessary for manipulating the interruption switch; and an alarm control device that causes an alarm device to issue an alarm only when the following conditions are all satisfied. The key switch is in the key-off state; the interruption switch is in the supply allowing state; the controller is being operated; and the sensor has detected presence of the interruption necessary motion.